Method of producing a dimensional stable fabric



United States Patent 3,310,856 METHOD 6F PRODUCING A DIMENSIGNAL STABLE FABRIC William T. Roff, In, and John A. Soltis, Spartanburg,

S.C., assignors to Deering Millilren Research Corporation, Spartanbnrg, S.C., a corporation of Delaware No Drawing. Filed Oct. 12, 1962, Ser. No. 230,292

6 (Ilaims. (Cl. 2875) This invention relates to sized fabrics which are free from hygroscopic properties and more specifically to sized dimensionally stable fabrics which are free from hygroscopic properties.

In textile operations the Warp yarns are commonly coated with a sizing composition in order to increase the strength and abrasion resistance of the warp yarns and thereby reduce breakage in subsequent weaving operations. The improvements to be had in utilizing sized warp yarns in weaving operations is so great as to make the use of sized warp yarns a veritable necessity. The component most commonly used as a sizing for warp yarns is starch. While starch sized warp yarns have greatly increased strength and abrasion resistance as compared with unsized warp yarns and while the starch s zed warp yarns weave well, it is found that the finished fabric having starch sized warp yarns exhibits hygroscop c properties due to the strong afiinity of starch for Water. Efforts have been made to remove the starch sizing and thereby avoid the annoying hygroscopic properties. These efforts of starch removal or desizing as it is known in the industry, have taken the form of treating the starch sized fabric with enzymes and with hot water. A fabric desized in this manner will not be completely free of starch, some residual amounts of starch and starch breakd wn products such as dextrin always remaining in the fabric. A starch desized fabric is also lacking in dimensional stability and in general has a limp and sleazy appearance.

In addition to the desirability of nonhygroscopic properties in a fabric, it is also desirable that the fabric have dimensional stability and especially multi-directional stability. While it is well-known to provide dimensional stability along the warp yarns of a finished fabric by sizing the warp yarns with starch, it is not common to have dimensional stability along the fill yarns of the fabric in that sizing of fill yarns is a ditficult and expensive operation. Attempts have been made to provide multi-directional dimensional stability in a fabric by coating the entire fabric with a stabilizing composition. The improvement obtained in dimensional stability by coat ng operations, however, is gained by sacrificing fabric weight and fabric flexibility. It can readily be seen that a nonhygroscopic fabric which would have multi-directional dimensional stability in addition to lightweight and flexibility qualities would be a major advance in the textile field, fabrics of this nature being highly sought after for use as ornamental coverings which must be stretched over a metal frame such as, for instance, awnings and automotive headlinings.

It is therefore an object of this invention to provide a method for the preparation of a sized fabric which is not sensitive to moisture.

It is another object of this invention to provide sizing compositions which are suitable for the preparation of a sized fabric which is not sensitive to moisture.

It is still another object of this invention to provide nonhygroscopic lightweight flexible fabrics having multidirectional dimensional stability.

Additional objects of this invention will become apparent from the following description.

In accordance with this invention it has now been discovered that a sized fabric may be prepared which is 3,31%,855 Patented Mar. 28, 1%67 not sensitive to moisture by sizing the warp yarns of the fabric prior to weaving operations with a sizing composition consisting of not less than 3% and not more than 25% and preferably 5% to 15% by weight of a Water-insoluble organic polymeric resinous material. The polymeric material should be of a particle size suitable for use in an aqueous emulsion or dispersion. A sizing composition which has been found to be particularly suitable is a sizing composition employing an organic polymeric material which is at least 50% by weight vinyl chloride with the remainder being methacrylate and preferably a sizing composition employing an organic polymeric material which is at least 50% by weight vinyl chloride with the remainder being vinylacetate and methylacrylate. The polyvinyl chloride containing sizing composition which is an aqueous sizing composition has a concentration of solids in the aqueous bath ranging from about "7% solids to about 12% solids. The preferred sizing baths of this invention also contain minor amounts (.01% to weight to 1% by weight) of antifoam agents such as, for instance, silicone antifoaming agents or other organic polymeric resin compatible antifoaming agents.

In preparing the fabric of this invention, the Warp yarns are impregnated with a dispersion of the polymeric material by passage of the warp yarns through a size box. The warp yarns are then dried, preferably by passage over a heating unit such as, for instance, a bank of infrared lamps. In the event that a thermosetting resin is employed as the polymeric material in the dispersion, the drying temperatures must not be so high as to cure the thermosetting resin. The warp yarns are then woven with an untreated filling yarn to produce a woven fabric. The finished fabric is characterized by a high degree of dimensional stability and is free of those hygroscopic tendencies of starch sized yarns which cause puckering in a steam treated fabric which is held under tension. It should be understood that the fabric may be fabrics other than cotton fabrics, that is to say, the weaving may be done with materials such as, for instance, wool, jute, hemp, ramie, sisal, flax, rayon, nylon and the like.

In order to obtain a high degree of dimensional stability, or more specifically multi-directiona1 dimensional stability, the warp sized fabrics of this invention should be passed into the nip of a suitable hot calender device. The calendering operation has the effect of producing interyarn bonding in addition to the interfiber bonding previously obtained in the warp yarns by means of the sizing operation. The heat and pressure of the calendering operation cause the resinous material adhered to the warp yarns to flow onto the fill yarns thereby adhering the warp t0 the fill yarns and giving the fabric multidirectional dimensional stability.

Where a hot calendering operation is employed in finishing the warp sized fabric, the warp yarns may be sized with a sizing composition containing water-soluble thermosetting resins such as, for instance, melamine formaldehyde, urea formaldehyde, phenol formaldehyde and the like. The heat of the calendering operation will substantially simultaneously cure the thermosetting resin and cause some quantities of the resin to flow onto the fill yarns of the fabric. The resultant product will be a nonhygroscopic fabric wherein the warp yarns are bonded to the fill yarns.

To determine the degree of multi-directional dimensional stability provided by hot icalendering the resin warp sized fabric of this invention, a cotton fabric having 38 Warp yarns and 36 fill yarns per square inch was sized prior to weaving operations in a manner such that the warp yarns had a 17% pickup of a :copolymer of vinylchloride and methylacrylate. The warp sized fabric was then cut into strips 2% inches in length by 1 inch in width, the 2% inch dimension being cut in a manner such as to leave a single warp yarn extending approximately A1 inch from the edge. This single centrally located warp yarn which extends beyond the edge of the test strip was then cut at a point 2 inches from the end having the overlapping warp yarn. The bottom of the test strip and the tip portion of the overlapping warp yarn were then locked in an Instron testing machine and the maximum pulling strength in grams was determined for that force necessary to separate the warp yarn from the fabric. A warp sized but uncalendered cotton fabric identical in all other respects was used as a control. It Was found by averaging 20 individual tests that 132 grams pulling strength were necessary to separate a warp yarn from the uncalendered warp sized cotton fabric. When, however, a copolymer sized cotton fabric was calendered at a temperature of 300 F., it was found, by averaging 20 individual tests, that a pulling strength of 237 grams was necessary to break a warp yarn loose from the fabric.

It should be appreciated that certain fabrics, due to yarn characteristics or due to a low number of picks and ends per unit area or due to a specific type of weave will have so little dimensional stability that the fill yarns will shift in a traversing fashion over the warp yarns. While fabrics having the aforementioned construction are desirable for many applications, the tendency of fill yarns to shift position is almost always a detrimental feature. When, however, warp yarn is sized with the organic polymeric resin sizing composition of this invention and the woven fabric is subsequently hot calendered the fill yarns will be heat sealed to the warp yarns and will not be able to shift or traverse along the warp yarns.

The following specific examples are representative of coating compositions which are suitable in sizing warp yarns in the preparation of nonhygroscopic dimensionally stable fabrics. The coating compositions of Examples III and IV are only employed in conjunction with a hot calendering operation. The examples, however, are merely illustrative and should not be considered as limiting the spirit or scope of this invention.

EXAMPLE I Parts Vinylchloride-methylacrylate copolymer (60-40 Glycerol 5 Dow Corning Antifoarn B (silicone defoamer marketed by Dow Corning Corp.)

Water 4 EXAMPLE IV Parts Phenol formaldehyde 18 Ethylene glycol 2 Dow Corning Antifoam B (silicone defoamer marketed by Dow Corning Corp.) 0.5 Water 79.5

The resin sized fabric of this invention may be employed as a fabric covering material as is, or may be laminated to a compatible resin film. Because of the nonhygroscopic properties of the resin sizing, the fabric of this invention need not undergo desining operations in order to prevent puckering of the material due to moisture absorption when the fabric is employed as a covering material. This characteristic in addition to the fabrics dimensional stability makes the fabric of this invention especially desirable for use as an upholstening material in automotive headlinings. Automotive headlinings are commonly installed by hanging on wires which fit into brackets on the automobile roof edges. As the installation is seldom perfectly taut, a steam hose is frequently inserted into the headlining hole used for the insertion of a dome light. The steaming will shrink the fabric so that the finished headlining is taut and trim. The relaxation which occurs upon cooling will not cause puckers which are common in starch sized fabrics due to the moisture retention of the starch.

What is claimed is:

1. A process for the preparation of an organic polymeric resin sized fabric comprising passing warp yarns through a coating composition comprising from 3% by weight to 25% by weight of a water-insoluble organic polymeric resin in an aqueous carrier and then weaving the sized warp yarns with filling yarns which are free of coating compositions capable of plasticizing the waterinsoluble organic polymeric resin so that the polymeric resin may cause adherence between the fabric yarns to produce a dimensionally stable fabric.

2. A process for the preparation of an organic poly meric resin sized fabric comprising passing warp yarns through a coating composition comprising from 3% by weight to 25% by weight of a vinylchloride-methyl acrylate copolymer in an aqueous carrier and then weaving the resin sized warp yarns with filling yarns which are free of coating compositions capable of plasticizing the water-insoluble organic polymeric resin so that the polymeric resin may cause adherence between the fabric yarns to produce a dimensionally stable fabric.

3. A process for the preparation of an organic poly meric resin sized fabric comprising passing warp yarns through a coating composition comprising from 3% by weight to 25% by weight of a vinylchloride-methylacrylate-vinylacetate terpolymer in an aqueous carrier and then weaving the resin sized warp yarns with fill yarns which are free coating compositions capable of plasticizing the waterinsolub1e organic polymeric resin so that the polymeric resin may cause adherence between the fabric yarns to produce a dimensionally stable fabric.

4. A method for the production of a resin sized fabric having multi-directional dimensional stability comprising passing warp yarns through a coating composition comprising from 3% by weight to 25% by weight of an organic polymeric resin in an aqueous carrier, weaving the resin sized warp yarns with unsized filling yarns and then passing the woven fabric into the nip of a heated pair of calender rolls whereby the resin sizing of the warp yarn will flow onto the fill yarns thereby bonding the warp yarns to the fill yarns and providing a high degree of dimensional stability.

5. A method for the production of a resin sized fabric having multi-directional dimensional stability comprising passing warp yarns through a coating composition comprising from 3% by weight to 25% by weight of a vinylchloride-methylacrylate copolymer dispersed in Water, weaving the resin sized warp yarns with unsized filling yarns and then passing the woven fabric into the nip of a heated pair of calender rolls whereby the resin sizing of the warp yarns will flow over the fill yarns thereby bonding the warp yarns to the fill yarns and providing a high degree of dimensional stability.

6. A method for the production of a resin sized fabric having multi-directional dimensional stability comprising passing warp yarns through a coating composition comprising from 3% by weight to 25% by Weight of a vinylchloride-methylacrylate-vinylacetate terpolymer dispersed in water, Weaving the resin sized warp yarns with unsized filling yarns and then passing the woven fabric into the nip of a heated pair of calender rolls whereby the resin sizing of the warp yarns will flow over the fill yarns thereby bonding the warp yarns to the fill yarns and providing a high degree of dimensional stability.

References Cited by the Examiner UNITED STATES PATENTS 2,539,301 1/1951 Foster 2873 2,879,581 3/1959 Evans et al. 2880 2,953,550 9/1960 Frostick et al. 117139.5 X 2,954,358 9/1960 Hurwitz 26029.6 2,999,297 9/ 1961 Schwartz 2880 3,021,318 2/1962 Laporta 117-139.5 X 3,025,255 3/1962 Lambuth 26029.3 3,045,317 7/1962 Shipman 2875 3,054,698 9/1962 Wagner 117-1395 X 3,074,898 1/ 1963 Luskin et al 26029.4 3,090,102 5/1963 Jannarelli 28-75 3,142,109 7/1964 Stoll et 'al 28--75 MERVIN STEIN, Primary Examiner. R. C. MADER, Examiner.

H. J. HAUDON, H. G. GARNER, Assistant Examiners. 

1. A PROCESS FOR THE PREPARATION OF AN ORGANIC POLYMERIC RESIN SIZED FABRIC COMPRISING PASSING WARP YARNS THROUGH A COATING COMPOSITION COMPRISING FROM 3% BY WEIGHT TO 25% BY WEIGHT OF A WATER-INSOLUBLE ORGANIC POLYMERIC RESIN IN AN AQUEOUS CARRIER AND THEN WEAVING THE SIZED WARP YARNS WITH FILLING YARNS WHICH ARE FREE OF COATING COMPOSITIONS CAPABLE OF PLASTICIZING THE WATERINSOLUBLE ORGANIC POLYMERIC RESIN SO THAT THE POLYMERIC RESIN MAY CAUSE ADHERENCE BETWEEN THE FABRIC YARNS TO PRODUCE A DIMENSIONALLY STABLE FABRIC. 